Method for the distillative purification of EDA

Patent metadata

Field	Value
Publication number	US-9828329-B2
Application number	US-201515125850-A
Country	US
Kind code	B2
Filing date	Mar 11, 2015
Priority date	Mar 13, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

The present invention relates to a process for purifying ethylenediamine (EDA) by distillation, wherein the process comprises the steps a) and b). In step a), a mixture (G1) comprising water, EDA and N-methylethylenediamine (N-MeEDA) is fed into a distillation apparatus (D1), and the major part of the water comprised in the mixture (G1) is separated off overhead at a pressure of greater than 4.8 bara. From the bottom of (D1), the water-enriched mixture (G2) is fed into a distillation apparatus (D2) in step b). At the top of (D2), the major part of the N-MeEDA is distilled off. The stream (S3) obtained from the bottom of (D2) comprises EDA, with the components water and N-MeEDA comprised in the mixture (G1) having been largely or completely removed. Further distillation steps can optionally be carried out in order to obtain pure EDA, for example when diethylenetriamine (DETA) is additionally comprised in the mixture (G1). If ammonia is additionally comprised in the mixture (G1), an ammonia removal is preferably additionally carried out before carrying out the step a) in the process of the invention.

First claim

The invention claimed is:

1. A process for purifying ethylenediamine (EDA) by distillation, comprising a) and b):
a) introducing a mixture (G1) comprising water, EDA and N-methylethylenediamine (N-MeEDA) into a distillation apparatus (D1), wherein
i) a stream (S1) comprising water is distilled off overhead from (D1) at a pressure of greater than 4.8 bara and
ii) a mixture (G2) depleted in water compared to the mixture (G1) is taken off from the bottom of (D1),

b) introducing the mixture (G2) into a distillation apparatus (D2), wherein
i) a stream (S2) comprising N-MeEDA is distilled off overhead from (D2) and
ii) a stream (S3) depleted in N-MeEDA compared to the mixture (G2) is taken off from the bottom of (D2).

2. The process according to claim 1 , wherein the mixture (G1) further comprises ammonia (NH 3 ) and the process further comprises removing of ammonia from the mixture (G1) c) and the removing c) is performed before the introducing of a mixture (G1) into a distillation apparatus (D1) a).

3. The process according to claim 2 , wherein the removing of ammonia c) is two stages, comprising
taking off ammonia overhead at from 20 to 70° C. from the mixture (G1) in a distillation apparatus (D3) and condensing, wherein the temperature at the bottom is less than 220° C. and a mixture (G1a) depleted in NH 3 is transferred from the bottom to a distillation apparatus (D4),
separating off the mixture (G1b) from the bottom in the second distillation apparatus (D4), wherein the mixture (G1b) is completely or largely free of ammonia and the mixture (G1b) is fed instead of the mixture (G1) into the distillation apparatus (D1) in the introducing of a mixture a).

4. The process according to claim 1 , wherein the EDA comprising the mixture (G1) is prepared by a process (A) or a process (B), wherein
i) the process (A) comprises (A1) to (A3)
A1) reacting formaldehyde and hydrocyanic acid (HCN) to form formaldehyde cyanohydrin (FACH), wherein the hydrocyanic acid is completely or largely free sulfur dioxide (SO 2 ),
A2) reacting FACH with ammonia (NH 3 ) to form aminoacetonitrile (AAN),
A3) hydrogenating AAN in the presence of a catalyst to form EDA,

ii) the process (B) comprises (B1) and (B2):
B1) reacting ethylene oxide (EO) with ammonia (NH 3 ) to form ethanolamine (EOA),
B2) reacting EOA with NH 3 to form EDA.

5. The process according to claim 4 , wherein the hydrogenating (A3) of the process (A) is carried out in the presence of a Raney catalyst.

6. The process according to claim 4 , wherein the hydrogenating (A3) of the process (A) is carried out in the presence of a Raney nickel catalyst or a Raney cobalt catalyst.

7. The process according to claim 4 , wherein the hydrogenating (A3) of the process (A) is carried out in the presence of a Raney cobalt catalyst comprising at least one selected from the group consisting of the elements Fe, Ni, and Cr as a promoter.

8. The process according to claim 4 , wherein the mixture (G1) further comprises ammonia and the process further comprises removing of ammonia NH 3 from the mixture (G1) c) before the introducing of a mixture (G1) into a distillation apparatus (D1) a), wherein the ammonia is separated off in the removing of ammonia c) and recirculated to a preceding process step, wherein the ammonia recirculation is performed after the reacting formaldehyde cyanohydrin with ammonia A2) of the EDA preparing process (A) or after at least one of the reacting ethylene oxide with ammonia B1) or the reacting ethanolamine with ammonia B2) of the EDA preparing process (B).

9. The process according to claim 1 , wherein the process further comprises d):
d) introducing the stream (S3) into a distillation apparatus (D5), wherein EDA is distilled off overhead from D5 at a pressure of from 200 mbara to 2 bara and the EDA has a purity of at least 95%.

10. The process according to claim 9 , wherein the EDA distilled off overhead has a purity of at least 99%.

11. The process according to claim 9 , wherein the EDA distilled off overhead has a purity of at least 99.5%.

12. The process according to claim 1 , wherein the mixture (G1) further comprises diethylenetriamine (DETA) and the process further comprises removing DETA e).

13. The process according to claim 9 , wherein the mixture (G1) further comprises diethylenetriamine (DETA) and the process further comprises removing DETA e) performed after the introducing of the mixture (G2) into a distillation apparatus (D2) b) or after the introducing of the stream (S3) into a distillation apparatus (D5) d).

14. The process according to claim 13 , wherein the stream (S3) comprises DETA and a stream (S4) enriched in DETA compared to the stream (S3) is taken off from the bottom of the distillation apparatus (D5) and the removing of DETA e) comprises:
e) introducing the stream (S4) into a distillation apparatus (D6), wherein DETA is distilled off via a side offtake from D6.

15. The process according to claim 1 , wherein, during the introducing of a mixture (G1) into a distillation apparatus (D1) a), the temperature at the bottom of the distillation apparatus (D1) is from 175 to 250° C. or wherein the water comprising the mixture (G1) is completely or largely distilled off overhead from (D1).

16. The process according to claim 1 , wherein the mixture (G2) taken off from the bottom of the distillation apparatus (D1) in the introducing of a mixture (G1) into a distillation apparatus (D1) a) comprises less than 1000 ppm by weight of water relative to the total weight of the mixture (G2).

17. The process according to claim 1 , wherein the mixture (G2) taken off from the bottom of the distillation apparatus (D1) in the introducing of a mixture (G1) into a distillation apparatus (D1) a) comprises less than 200 ppm by weight of water relative to the total weight of the mixture (G2).

18. The process according to claim 1 , wherein the mixture (G2) taken off from the bottom of the distillation apparatus (D1) in the introducing of a mixture (G1) into a distillation apparatus (D1) a) comprises less than 50 ppm by weight of water relative to the total weight of the mixture (G2).

19. The process according to claim 1 , wherein the distillation apparatus (D2) in the introducing of the mixture (G2) into a distillation apparatus (D2) b) is operated at a temperature at the bottom of from 20 to 75° C. or at a pressure at the top of from 10 to 500 mbara.

20. The process according to claim 1 , wherein the distillation apparatus (D2) in the introducing of the mixture (G2) into a distillation apparatus (D2) b) is operated at a pressure at the top of from 50 to 200 mbara.

21. The process according to claim 1 , wherein the stream (S3) taken off from the bottom of the distillation apparatus (D2) in the introducing of the mixture (G2) into a distillation apparatus (D2) b) comprises less than 10000 ppm by weight of N-MeEDA relative to the total weight of the stream (S3).

22. The process according to claim 1 , wherein the stream (S3) taken off from the bottom of the distillation apparatus (D2) in the introducing of the mixture (G2) into a distillation apparatus (D2) b) comprises less than 1000 ppm by weight of N-MeEDA relative to the total weight of the stream (S3).

23. The process according to claim 1 , wherein the stream (S3) taken off from the bottom of the distillation apparatus (D2) in the introducing of the mixture (G2) into a distillation apparatus (D2) b) comprises less than 200 ppm by weight of N-MeEDA re

Assignees

• Basf Se

Inventors

• Luyken Hermann
• Jaegli Stephanie
• Lorenz Michael
• Brasche Gordon
• Jegelka Markus
• Becker Barbara
• Baumann Robert
• Melder Johann-Peter
• Buschhaus Boris
• Krug Thomas

Classifications

• C07C209/84 Primary

  Purification · CPC title

• C07C253/08

  by addition of hydrogen cyanide or salts thereof to unsaturated compounds · CPC title

• C07C209/16 Primary

  with formation of amino groups bound to acyclic carbon atoms or to carbon atoms of rings other than six-membered aromatic rings · CPC title

• C07C209/48

  by reduction of nitriles · CPC title

• C07C213/04

  by reaction of ammonia or amines with olefin oxides or halohydrins · CPC title